Authorities in Mexico have pulled out at least 12 bodies from a well in the northern state of Nuevo Leon near where a Colombian-style band went missing last week.
The Monday afternoon discoveries, along a dirt road in the small town of Mina, close to the northern Mexican city of Monterrey, came days after police initially began scouring the area for 20 missing members and crew of the band Komo Kolombia.
"The search will continue ... to see how many more bodies may be hidden there," Jorge Domene, Nuevo Leon state security spokesman, said.
Domene said the survivor, a member of the band, told police the 18 were blindfolded and driven on dirt roads until they stopped.
He then heard the assailants ask fellow band members if they belonged to a drug cartel, shots were fired and the bodies were dumped into a well.
Domene said the survivor, who is being protected by soldiers, was able to reach a nearby ranch and get help. He would not give details on how the man was able to escape.
The man later led authorities to the well where searchers found several bodies, Domene said.
Domene said four bodies first pulled from the well on Sunday have been identified by their relatives, including a Colombian citizen who played the keyboard. Three of them were wearing matching T-shirt with the name of the band.
The bodies recovered showed signs of torture, said a forensic official, who spoke on condition of anonymity because he was not authorised to comment publicly on the case.
It was hard to determine how many more bodies were submersed in the water, he said.
Authorities initially said 16 members of the band Kombo Kolombia and four crew members were reported missing early on Friday after playing at a private party attended by about 50 people and held at a ranch called La Carreta, in the town of Hidalgo, north of Monterrey.
Domene said 18 band members had gone missing. He did not say how many were crew members and how many were musicians.
The party guests are being questioned and police have yet to determine a motive in the killings, Domene said.
Nuevo Leon state, on the border with Texas, has been the scene of a turf battle between members of the Gulf drug cartel and the Zetas drug gang.
People living near the ranch in Hidalgo reported hearing gunshots at about 4am Friday, followed by the sound of vehicles speeding away, according to a separate source with the Nuevo Leon State Investigative Agency.
He also spoke on condition of anonymity because he was not authorised to be quoted by the news media.
Relatives filed a missing-persons report on Friday after losing mobile-phone contact with the musicians. When they went to the ranch to investigate, they found the band members' vehicles still parked outside.